What Is Known About Chlodantane Chemistry

A PubMed query run on 21 September 2026 for chlodantan* returns exactly one record. Not one review, not one recent paper — one record in total, a Russian-language article from 1999. The same database, queried the same way for bromantane, returns 34.

That ratio is the honest starting point. What is known about chlodantane chemistry is almost entirely structural: an unambiguous identity, a molecular formula, a functional group, and a cage that organic chemists have understood since the 1960s. What is not known is nearly everything else, and this article is explicit about which is which rather than smoothing the gap over.

What the public databases actually hold

PubChem resolves the name to CID 959689: N-(adamantan-2-yl)-4-chlorobenzamide, molecular formula C17H20ClNO, molecular weight 289.8, InChIKey VOHIYJJUKAUCCU-UHFFFAOYSA-N. The associated CAS Registry Number is 185384-80-9.

The synonym list is the more informative field. PubChem returns five entries for this compound: the CAS number, “Chlodantane”, a DSSTox identifier, and two systematic name variants. For comparison, the PubChem entry for mebicar carries seventy-seven synonyms. Synonym count is a rough proxy for how many independent databases, catalogues and publications have ever referred to a substance, and five is close to the floor.

A note on method, because a negative result is only as good as the instrument. The search above was repeated with three spellings — chlodantane, chlodantan and the truncation chlodantan* — and separately as a structural query combining “adamantyl” and “chlorobenzamide”, which returned zero records. The same instrument returns 34 records for bromantane, so it is not simply blind to Soviet-era adamantane compounds. The absence is in the literature, not in the query.

Chlodantane is an amide, bromantane is an amine

Chlodantane is routinely described as the chlorine analogue of bromantane. Read the two structures from PubChem and that description collapses.

	Chlodantane	Bromantane
PubChem CID	959689	4660557
Name	N-(adamantan-2-yl)-4-chlorobenzamide	N-(4-bromophenyl)adamantan-2-amine
Formula	C17H20ClNO	C16H20BrN
Molecular weight	289.8	306.24
Nitrogen environment	secondary amide	secondary arylamine
Aryl ring attached to	carbonyl carbon	nitrogen

In bromantane the aromatic ring is bonded directly to nitrogen: it is a diarylamine-type secondary amine, and the nitrogen lone pair is delocalised into the ring. In chlodantane the aromatic ring is bonded to a carbonyl carbon, and the nitrogen lone pair is delocalised into the C=O group instead. Chlodantane contains an extra oxygen and one fewer carbon in the formula, which is exactly what swapping an N-aryl bond for an N-acyl bond does.

These are different functional classes with different hydrolytic stability, different infrared signatures, different basicity and different chromatographic behaviour. Calling one the halogen analogue of the other is a naming convenience, not a structural statement.

Why the 2-position of the adamantane cage matters

Adamantane itself is thoroughly characterised. The NIST Chemistry WebBook lists it under CAS 281-23-2, formula C10H16, molecular weight 136.2340, systematic name tricyclo[3.3.1.1(3,7)]decane. It is the smallest hydrocarbon fragment with the diamond lattice geometry, which is why the cage is conformationally rigid: there is no ring-flipping to speak of.

The cage has two distinct substitution sites. The four bridgehead carbons (position 1 and equivalents) are tertiary; the six CH2 carbons (position 2 and equivalents) are secondary. Schleyer and Nicholas devoted a 1961 paper in the Journal of the American Chemical Society to the preparation and reactivity of 2-substituted adamantane derivatives precisely because that position behaves unlike the bridgehead.

Both chlodantane and bromantane are substituted at C-2, not at the bridgehead. One consequence is worth stating because it is often got wrong: substitution at C-2 does not create a stereocentre. A mirror plane still passes through C-2 and its substituent, so the two ring branches remain equivalent and the molecule is achiral. No chiral chromatography is needed, and no enantiomeric excess exists to report.

What is known about chlodantane chemistry from the single published record

The one indexed paper is Morozov, Klimova, Sergeeva, Ivanova, Barchukov, Kovalev, Piatin and Avdiunina, “Adamantane derivatives enhancing body’s resistance to emergencies”, Vestnik Rossiiskoi Akademii Meditsinskikh Nauk, 1999, issue 3, pages 28-32, PMID 10222828. It is in Russian.

Its abstract states that 329 novel adamantane compounds were synthesised and evaluated, and that halogen-substituted aromatic derivatives at the second position had the most pronounced effect on the resilience of animals in the models used. Chlodantane is described there as a rapid-acting adaptogenic agent in animal experiments. Bromantane is discussed alongside it.

That is the whole of the indexed primary record. It reports no melting point, no spectroscopic characterisation and no analytical method for chlodantane that can be read from the abstract, and it is an animal study. Two related items exist in the Pharmaceutical Chemistry Journal — a 2000 review of adamantane pharmacology and toxicology by Spasov, Khamidova, Bugaeva and Morozov, and a 2017 synthesis paper by Babushkin and colleagues on conformationally labile bromantane analogues — but both sit behind a paywall that blocked access during this research, so they are cited here for their existence and nothing is drawn from their contents.

What a certificate of analysis can establish when the literature cannot

A compound with no literature is not a compound with no measurable properties. Everything below is determinable in a competent laboratory without reference to any prior publication.

Nuclear magnetic resonance. The 4-chlorophenyl ring gives a characteristic para-disubstituted two-doublet aromatic pattern. The adamantan-2-yl group gives a distinctive high-field envelope, with the C-2 methine shifted downfield by the adjacent nitrogen.
Infrared spectroscopy. A secondary amide shows a carbonyl stretch and an N-H stretch. Their presence separates chlodantane from an arylamine such as bromantane immediately, with no chromatography at all.
Mass spectrometry. One chlorine atom produces a pair of molecular ions two mass units apart. NIST gives the isotopic composition of chlorine as 0.7576 for chlorine-35 and 0.2424 for chlorine-37, so the pair appears in a roughly three-to-one intensity ratio. A bromine-containing impurity would show a near one-to-one pair instead, which makes cross-contamination between these two adamantane compounds trivially visible.
Chromatographic purity. The chlorophenyl chromophore is a good ultraviolet absorber, so HPLC with diode-array detection is straightforward.

This is the sensible reading of a compound in this position: it is a well-defined analytical reference standard whose identity and purity can be documented, sitting on top of a pharmacological record consisting of one abstract. The two claims should never be merged into one sentence. The conditions of supply for material of this kind exist for that reason.

What should be written down as unknown

Based on the searches performed for this article, the following are absent from the indexed literature and should be reported as absent rather than estimated: any human study of chlodantane; any published crystal structure; any validated bioanalytical method; any dose-response or toxicological dataset indexed in PubMed; any pharmacokinetic description. A single Russian-language abstract from 1999 is the entirety of the indexed primary evidence.

An empty record is a finding. It tells a chemist that anything written about this compound beyond its structure needs a citation attached, and that most of what circulates online has none.

Frequently asked questions

What is the CAS number of chlodantane?

PubChem CID 959689 lists CAS Registry Number 185384-80-9 for chlodantane, corresponding to N-(adamantan-2-yl)-4-chlorobenzamide. The same entry gives the molecular formula C17H20ClNO, a molecular weight of 289.8 and the InChIKey VOHIYJJUKAUCCU-UHFFFAOYSA-N. Only five synonyms are recorded in total, which is unusually few.

Is chlodantane the same as bromantane?

No, and they are not simple halogen analogues either. Bromantane is N-(4-bromophenyl)adamantan-2-amine, an arylamine in which the aromatic ring is bonded to nitrogen. Chlodantane is N-(adamantan-2-yl)-4-chlorobenzamide, an amide in which the aromatic ring is bonded to a carbonyl carbon. They share the adamantan-2-yl group and nothing else in the linkage.

How many papers on chlodantane are there in PubMed?

One, as of 21 September 2026. A truncated search on chlodantan* returns a single record: a 1999 Russian-language article in Vestnik Rossiiskoi Akademii Meditsinskikh Nauk, PMID 10222828. A structural query combining adamantyl and chlorobenzamide returns zero records. The same database returns 34 records for bromantane.

Has chlodantane been studied in humans?

No human study of chlodantane appears in PubMed. The single indexed record describes experiments in animals. Any statement about effects in people therefore has no indexed primary source behind it and should be treated as unsupported until a citation is produced.

Why is the 2-position of adamantane different from the 1-position?

The four bridgehead carbons of the adamantane cage are tertiary, while the six methylene carbons are secondary, and they differ in reactivity and in how substituents are introduced. Schleyer and Nicholas published a dedicated study of 2-substituted adamantanes in 1961 for that reason. Substitution at C-2 also leaves a mirror plane intact, so the product is achiral.

How do you characterise a compound that has almost no published literature?

By measurement rather than citation. Nuclear magnetic resonance establishes the carbon skeleton, infrared spectroscopy confirms the amide carbonyl and N-H, high-resolution mass spectrometry confirms the elemental composition, and the chlorine isotope pattern confirms a single chlorine atom. Chromatographic purity is then reported against a stated method. None of this requires prior publications.

What does the chlorine isotope pattern look like in mass spectrometry?

A molecule with one chlorine atom gives two molecular ion peaks separated by two mass units. NIST gives chlorine-35 an isotopic abundance of 0.7576 and chlorine-37 an abundance of 0.2424, so the two peaks appear in roughly a three-to-one ratio. Bromine, by contrast, gives a near one-to-one pair, which distinguishes chlorinated from brominated analogues at a glance.

References

Research use only. Nonsensia Lab supplies analytical reference standards for laboratory and research applications. This article is published for scientific and educational purposes. It is not medical advice, it does not describe any use in humans, and nothing in it should be read as a recommendation to administer any substance to a person or animal.

Filed under: Chemistry & Discovery

This article is part of our guide to Where Research Compounds Come From: Discovery, Synthesis and Structure.

The compound discussed in this article is available as an analytical reference standard: Chlodantane – Analytical Reference Standard | CAS 185384-80-9.

Chlodantane: The Adamantane Analogue Almost Nobody Has Characterised